Saturday, June 27, 2009

Rain Catch Barrel

My house was build in 1920. It originally had a cistern to catch and use rain water. At some point modernity rendered such technology obsolete. Now ecological awareness and and renewable energy concerns are making such old technology cutting edge again.

My local building centers sell plastic barrels for catching rain at premium prices. It is easy to spend $100 to $150 dollars for such a system.

My choice was to build my own out of a plastic garbage can. I did so for about $50. Still a lot of money for something that should be simple. $30 for a heavy duty garbage can. The rest on assorted hardware and sealants.This picture is of the outside of barrel with faucet.Now for some fun math. My city water rate is $2.58/100ft³ during the summer months when my rain catch will be used. (My city water is cheaper in the winter) I will be able to fill and use 31 gallons of water during each rain filling event. I'm guessing I can fill my barrel 10 times a year.Inside of the barrel bottom hardwareEach time I fill my 31 gallon barrel with free water I will get 4.14ft³ or 9.5cents of water. This will provide a net savings of about $1 per year.

If I stay active and am lucky with my health, I might see a profit in 50 years so long as no mechanical parts fail in the next half-century.Outside barrel bottom hardware without faucet.I didn't do the math before building the rain catch, but I am not surprised at the lack of savings.

Assuming such a barrel has a 10 year functional life span. It would have to cost less than $10 dollars to be of economic value.

Thus, I've concluded current rain catch barrels are products for eco-snobs who prominently display systems next to hybrid Escalades. Admittedly, they must also be products for geeky, cheap, eco-snobs who build them for half price.

This project was not merit less. Putting a barrel under a gutter down spout seems so easy, but there were a number of fun challenges to solve. I also enjoyed dabbling in old technology.

I'm left with several questions stemming from my work. In 1920 catching rain water made enough sense to have a dedicated, built-in system in my house. What's changed? Has water become that much less expensive? Could a past system collect much larger quantities of water? Was it a labor saver due to the lack city water? What elements of modern living forced the obsolescence of this system?

Finally, why do I feel like this project was $50 dollars well spent? I'll post more pictures when the system is working.